Parameters for natural resistance in bovine milk

Parameters for natural resistance in bovine milk
Mastitis or udder inflammation is one of the most important health problems of dairy cattle. Resistance against mastitis and many other diseases is partly based on the naturally present disease resistance capacity: innate immunity. This research therefore aimed to identify adequate immune parameters and determine their relation with the susceptibility of the individual animal for mastitis and possibly also other health problems. Natural antibodies (NAb) were found suitable to further study their relation with natural resistance of dairy cows. Heritability of NAb in milk samples of heifers (cows that had a calf for the first time) was low to moderate, which gives potential for genetic selection. It should, however, be investigated if selection for improved NAb levels has unintentionally also negative relations with other selection traits. Furthermore, NAb could also be influenced by management factors, but this would be a subject for future study. Besides, results suggested that higher levels of certain NAb in milk can decrease the risk for high Somatic Cell Count (in heifers), clinical mastitis and genital organ and fertility problems. However, heifers appear to differ from older cows in the relation of their NAb levels with risk for CM and high SCC, and the (udder) health history also affects this relation.